This invention relates to a television receiver, and more particularly, a circuit for detecting and improving its operation state.
In a television receiver, proper measures need to be taken against various undesirable operational states, such as, mistuning of the local oscillator which controls channel selection, nonsynchronization of either the vertical or horizontal scanning signals with the synchronizing signal, and excessive noise. For example, it is desirable to indicate to a user the receiving condition of a tuner, the non-synchronization of the scanning signals and to permit the user to correct such conditions. It is also desirable to automatically mute the loudspeaker when a noise signal is superimposed on the audio signal.